Radare2 is a command-line reverse engineering framework designed for analyzing binary files, firmware, and malware. It is used to disassemble, debug, analyze, and profile executable files, and has a modular and customizable architecture that allows users to create their own plugins and scripts. Radare2 is commonly used by security researchers, malware analysts, and vulnerability analysts to reverse engineer and understand how software works. It requires specialized skills in reverse engineering and command-line interface usage.